The following thumbnails are a measure for the background noise level at each VEBSN station,
as function of time. Each thumbnail displays the power of the background noise in two frequency bands.
The red curve reflects the long period noise (between 0.05 and 0.1 Hz),
while the blue curve reflects the short period noise (between 0.1 and 1 Hz).
Each thumbnail is coded by network, station, location and channel. The horizontal axis covers the current calendar year.